In the course of refining petroleum to produce fuel, lubricant, and petrochemical starting material products, there are various streams of intermediates created. Some of these streams are high in C.sub.8 's, and contain in particular some styrene and/or some ethylbenzene, which is a material related to styrene in that hydrogenation of styrene will produce ethylbenzene, and dehydrogenation of ethylbenzene will produce styrene. Because of its tendency to dimerize and polymerize, styrene is considered to be a troublesome component of gasoline stock intended ultimately for fuel use. Furthermore, use of styrene in fuel is not as high an economic use for the product as other petrochemical uses, such as a starting material for making polystyrene. In addition, there is a growing demand for polystyrene type products, and hence a growing demand for styrene as a starting material or precursor of such products.
In the above-mentioned parent application from which the present application is a continuation-in-part, there are disclosed techniques for separating styrene from other materials commonly found in pyrolysis gasoline, especially mixed xylenes and ethylbenzene.